Decomposition of Acid Azo Dye by Ozone

摘要

Ozonation has been applied to many areas in water and wastewaterrntreatment. Especially for textile mill effluents, ozone treatment canrnachieve high color removal, destroy aromatic compounds, enhancernbiodegradability, and then reduce the chemical oxygen demand (COD).rnThe objective of this research work is intended to study the ozonationrnof commercialized azo dye, I.e. Acid Orange 6, for evaluating itsrnozonation kinetics and color removal efficiency in a laboratory scalernsemi-batch reactor.rnThe results of this investigation indicate that as ozonation timernincreasing, the pH and conductivity in target solution are shown asrnopposite trends, as pH decreasing and conductivity increasing.rnDecolorization, determined by measuring the light absorbance ofrnwavelength at visible range (400-7000 nm), was almost removed withinrn90 minutes under two ozone dosages of 8 and 3 mg/L/min. The lightrnabsorbance of samples at wavelength of 254 nm (UV254) was recordedrnas an indicator of organic species, that have unsaturated bonds and/orrnaromatic structure, that reduced significantly in test runs. COD andrnTOC removal can reach as high as 80 and 58% under two ozone dosesrncondition respectively.